A randomized controlled study to assess patients' understanding of and consenting for clinical trials using two different consent form presentations

Abstract

Background: Informed consent is the ethical basis for clinical research. The physical appearance of the consent document may influence patients' willingness to carefully read the consent document. We therefore tested the hypothesis that presentation of consent documents in an enhanced format improves patients' attention, understanding and therefore willingness to consent for clinical research.

Methods: Patients being asked to participate in three large clinical trials were randomly assigned to enhanced or routine presentation. The enhanced document was printed on 20-pound, cream-colored bond paper and presented in a blue folio. In contrast, patients assigned to routine presentation were given an otherwise identical stapled set of photocopied pages. The primary outcome was the effect of the enhanced format on the proportion of patients consenting; the major secondary outcome was patient's understanding of the presented procedures and risks.

Results: A total of 189 of 251 (75%) patients approached with standard format consenting documents consented for an underlying study, whereas 164 of 248 (66%) approached with enhanced format documents consented; the adjusted odds ratio (95% confidence interval) for consenting (comparing enhanced to standard formats) was 0.64 (0.43, 0.95), P=0.03. About 90% of the patients in each group correctly identified the major study intervention and major associated risk. Neither patients' characteristics nor understanding affected the consenting rate for the presented clinical research.

Conclusion: Consent forms in an enhanced format (i.e., printed on fine paper and presented in a folio) did not improve patients' understanding or willingness to consent to participate in clinical trials.